I don’t think the issue would be within a players club itself, with team mates, nor the clubs fans.
The main issue would be the media coverage it would create in the tabloids, and the subsequent digging into their personal life. They would temporarily become one of the most famous footballers in the world, if they play in a top league.
The other issue would be opposition fans, there is no way a player would not get a few homophobic comments and sniggers when playing at an away ground, especially in Scotland.
If players feel they wish to come out, then what would be best if several players came out at the same time, together. That way it would spread the burden and responsibility and show it is more common in the game than people think, and hopefully it would then be more quickly accepted within the media and stands.
Weirdly enough, players would probably get less stick from the stands playing in a professional, high profile, modern environment, like the EPL, compared to somewhere like the Scotland. Imagine the stick a gay Rangers player would get at Parkhead, Pittodrie or Easter Road. If he was black and English as well then he would probably get lynched in Scotland, as we as a nation are not as tolerant or liberal as some would have you believe. Many will say they are, but it does not take much for the bitterness, jealousy, and agendas to come to the fore, the so called left wing have somehow become more zealous in their behaviour recently in their rush to be seen as woke in every respect.
Although it would be amusing seeing the SNP and liberal nationalists rush to defend and support a Rangers player for a change. Or maybe that would be a step too far.