Boniface VIII uses “EENS” as a premise to develop the further teaching that submission to the pope is necessary for salvation. That is a step beyond EENS. If you don’t believe me, read the document yourself. Similarly, Florence does not just reiterate EENS
My dear brother SH,
I’m afraid that in terms of being “subject to the Pope” as essential for salvation, you have once again jumped the gun, interpreted the text for yourself rather than study the uses of this phrase by previous Popes and theologians in the Middle Ages, and come up with a personal understanding of the text in opposition to the Church’s. Thus we go from supposition to supposition.
Pope Innocent IV (c. 1195 – 1254) - that’s just a few decades before the papacy of Pope Boniface VIII began in 1294 - understood being “subject to the Roman Pontiff” in a very different way from the
personal understanding that you espouse.
Read this, speaking about Innocent IV’s thoughts on “Infidel Dominium” (the Medeival Church doctrine that infidels - people neither Christian nor Jewish - had the right to ‘dominium’, self-government and independence):
“…[According to Innocent IV] the legitimate exercise of dominium did not exempt those infidels who possessed it from being judged by a higher authority, that is, the Pope. Responsible for ensuring the spiritual well-being of mankind, the Pope’s mission to guide humanity to salvation extended well beyond the physical members of the Church. As God’s agent on earth, the Pope therefore incurred the obligation of exercising judgement over all people, according to the law to which they were subject - Christians by Christian law, Jews by Jewish law and infidels by natural law…Pope innocent IV believed that papal jurisdiction over infidels was
de iure becoming only
de facto if natural law, the law known to all men, was violated…As such, any assesment of infidel actions on the basis of natural law meant that the latter were subject to papal definition. The emphasis on the legitimacy of infidel domnium, the ‘natural right of all men’, was qualified in that it required submission to papal consideration…”
Now, as someonme attracted to Eastern Orthodoxy, you may not like this exalted view of the papacy - for which I apologize in advance - however does it not make better sense to understand the context from which Boniface VIII made his statement rather than interpreting it yourself?
Now let us read Boniface’s statement in the light of his predecessor Innocent’s teaching above which is outlined in
Quid super his - a commentary on a decree of his predecessor Innocent III, Innocent IV being himself a canon lawyer. And lo and behold guess who Pope Boniface VIII references in his bull
Unam Sanctum in support of his statement that “every creature” must be subject to the roman pontiff? The bull contains writing from the letters of Innocent III! Yes the Pope who outlined the above teaching on the authority of the Pope over the souls of those outside the Church which was subsequently codified by his successor Innocent IV!
**"…Furthermore, we declare, we proclaim, we define that it is absolutely necessary for salvation that every human creature be subject to the Roman Pontiff…" **
Read in light of the teachings of his predecessor which he references in the Bull to back up his definition, the Medeival papacy believed that it
did in fact already posses jurisdiction over
all human beings whether bodily within or outwith the Church. This ties in perfectly with the Church’s teaching on “spiritual membership” and further strengthens the Church’s understanding of EENS over and against your own. A voice heavily noticed in the bull is Egidius Romanus (Giles of Rome), who some hold might have been the actual writer of the bull. In his writing
On Ecclesiastical Power, Giles voices the supremacy of the Roman Pontiff over the material world. His line of argument states that since the body is governed by the soul and the soul is governed by the ruler of the spiritual, the Roman Pontiff therefore is governor of both soul and body - believers in terms of both, and infidels only in soul.
According to Boniface’s predecessors
everybody is subject to the Roman Pontiff whether they like it or not, since his spiritual jurisdiction extends well beyond the confines of the Church as he is responsible for the salvation of all human beings according to the respective ‘law’ which they follow - Christian law for those within the Church in body, Jewish law for Jews outwith the Church and Natural law for infidels.
Rather than interpret this statement in the context of the references used within the Bull itself and with an understanding of the theology of the time from which it ermeged, you have read it with your own personal understanding and have done precisely what the Holy Office warned against in 1949.
This statement from Boniface VIII says absolutely nothing about the necessity of being
bodily a member of the Church or bodily subject to the Pope, which the Church has never believed or taught. After all many of its saints, such as SAINT EMERENTIANA, ST. RESPICIUS, the brother martyrs SAINTS DONATIEN AND ROGATIEN, ST VICTOR OF BRAGA - all of whom are valid saints - were never baptised with water but died catechumens - baptised therefore by baptism of desire alone. If the Medeival Church had believed in the doctrine of EENS you erroneously propose, that bodily membership was necessary to be incorporated into the Church, then they would not have been able to publically venerate these saints who had never received water baptism nor were ever bodily subject to the pope.
You remind somewhat of those people who pick verses out of the OT without context, such as conquest of Caanan in Joshua, to depict God as a “moral monster”.
Much love
The Universe is Catholic (Universal) 
We have but scratched the surface of 2,000 years of doctrinal exposition and development…