As well as uploading your raw data to My Heritage, I believe you can do the same with FTDNA, however there is a cost to unlock the useful features.
Neither of those sites are as popular as Ancestry so there are likely to be fewer matches (though people do transfer their data from other sites), but you might find some of the features, such as chromosome browser and Autocluster reports quite handy. I am amazed that Ancestry don’t offer these.
I hope you do hear from your 580cm match. A nice friendly cheery follow up email might be worth a try in a week or so if you don’t hear back. With the UK currently overrun with covid, you might need to consider that those you contact may be ill so they may not be able to get back to you straight away. In the mean time, concentrate on those who match with both you and the 580cm match.
It can be a waiting game too, and you don’t know what might be around the corner - the results of all those test kits bought as Christmas presents should be filtering through soon. There is hope.
DNA can sometimes be a bit randomly passed down so keep an open mind, eg my daughter shares more DNA with common matches than I do, my father has matches which I do not have .... etc etc.
Understandable that you want to protect your father. You come across as a very nice person.
Let us know how you get on. If you need specific help or even a second opinion, there are plenty of knowledgeable people on rootschat who would be happy to help - don’t hesitate to ask.