First of all, congratulations on raising that money for charity. That's excellent. I've just followed your channel and will definitely check in next time I see you live.
I've been streaming fairly regularly since the first lockdown last year, and despite some ups and downs it's been a real boost for me on the whole. I wrote some thoughts / advice for somebody else a little while back in a different thread, so apologies if you've already seen that as I'll repeat myself massively here!
Some points around trying to increase your following:
Seek out other streamers you enjoy and spend some time offering them the same type of interaction you're looking for from your followers. Don't just check out their stream once, drop them a follow and then disappear. Pop up in their streams regularly and comment on the games, or something they said, or ask them questions. If you build up a rapport, then more often than not they'll get around to checking out your stuff too. Not all of them will, and that's fine; if you still find them entertaining or interesting to watch, keep doing it and learn from what you think they do well.
This might sound completely obvious, but when you do get people watching, do what you can to engage with them. (I've checked out your latest stream and you seem naturally good at this.) Acknowledging their comments is great. Using those comments to riff off is better. Asking them questions of your own to keep the interaction going is better still. If someone feels welcome and valued when watching your stream, the chances are they're going to come back.
A regular time slot for streaming definitely helps, so stick to that if you can. That said, that's a really difficult area for me to stick to currently and I've managed to keep a small following, so it's not absolutely essential.
Maybe the most important point: embrace the fact that you're not going to be for everyone. People will come by, watch for a few minutes and drift away. Don't take it personally. If you try and be everything to everyone, you won't be able to keep it up. Do it for the fun of it first and foremost. If people see you having a great time doing it, the right ones will stick around / come back. You mentioned in your recent stream that you have your live viewer count turned off, which will help here massively!
On a similar point - you mention playing Osu because a regular viewer keeps bugging you to do it. I totally get the impulse to do that and keep a viewer happy and interested, but on the whole I would absolutely recommend you stick to playing stuff that you want to play. I have a thing where people can select games for me to play in the future using a big chunk of channel points. That way, regulars can have an input on what gets played on stream sometimes, but I also have rules in there so that if I detest the game after an hour or two, that counts as me having played it and I can move onto something else.
If you get a chance, try and build out your About page a bit more. Let people know what you're all about, your schedule, etc. I did nothing with mine for ages but as soon as I did I was surprised at the number of people who came in and commented on something I'd written in my introduction, etc.
Raids! I'm not sure if you usually do it, but I noticed you didn't raid at the end of your latest stream. This can be a great way to build up a connection with other streamers. Pick people you like and actively enjoy watching, and stick around for a while after you raid and interact if you can.
Sorry, that went on a bit! Having watched your latest stream, my initial impression is that you'll definitely be able to build an audience. I thought you were engaging and interacted well with the chat which is at least half the battle. The camera set-up and transition stings, etc. are really nice too. (I don't have any of that stuff yet as I currently stream audio-only direct from console, but plan to get a PC soon and upgrade that side of things.)
Anyway, good luck with it and I'll definitely be dropping by when I can. In the meantime, if you need any specific advice or want to bounce any questions/ideas off somebody, I'd be more than happy to help.