Honestly, in your case, you may want to think about how you work out the cost of running your site and include the value you place on your time within it. You're obviously not the most technically savvy in terms of running a web server (and I mean zero disrespect in saying that) and seem to spend a lot of time doing things on that side with varying levels of success. So, if you took all of that off of your plate, how much extra value could you add to your site with the additional time which would be available to you? Only you know the answer to that, but I think it's a worthwhile consideration.
When you say it's slower - bear in mind that on here as an example, you're connecting to the USA, you can have your site hosted in the EU. We fairly recently moved over to the cloud, and like you are UK based with a mostly UK audience and we / our users haven't noticed any speed drop. In fact, it's probably a bit faster than our previous platform.
People have already covered the third point, but suffice to say we've not missed having FTP access and what have you and have used the pages platform to add an ads.txt file and what have you - it's very straightforward to do.
I'm not here to pitch the cloud to you, I've no skin in the game so to speak, but based on your posts in here and the struggles you've been having at times, I actually think you could benefit from it.