I have a similar dilemma.
both the e-one and DGT look very attractive.
I understand that the DGT has/has had issues with connecting to chess.com.
I understand that the issue lies with the software on the smartphone and not with the hardware per se.
like you, I use iOS and am not sure if this issue is solely with iOS or whether android users also have this issue too.
I don’t know if this issue has been fixed.
I do know that there appears to be at least two camps that ‘fight their corner’.
those that believe Millenium has the superior product and those that believe DGT does.
it seems, from the online reviews I have read, that Millennium does not have such pronounced connection issues, but who knows. I am going for DGT simply because I have their Centaur chess computer acomputer.
I'd love to buy an electronic chess board to play online games, and have found the above three boards. Does anyone own one, and if so what are the pros and cons of that board and would you recommend? For info I live in the UK and use iOS and a Mac to connect to both chess.com and lichess.