I use a photo editor and/or vector program once every few months, and just about every time I start your software, there's an update.
While it's highly commendable that you update this often, not having an auto-update feature upon startup is inexcusable in 2021. Auto-update upon startup is more than enough; maybe add a 'not now' and 'ignore this update' button) for those that don't want to do it right away. Please do not install another piece of spyware systemtray icon that sits there eating up CPU power and RAM and that downloads the updates and manages my entire Affinity suite; don't be like Adobe, we choose Affinity because we got sick of Adobe.
A simple auto-update upon startup is more than enough... it's already better than what we have now!
Having to go to your website, manually downloading the new version and having to install it is really tedious when you have to do it EVERY TIME you start a piece of software; forcing this process on your users makes them disable the update checker and miss out on great new features (and you lose sales because they stop talking about those great features to other people).
Look at how Discord, Teamspeak, Firefox, Spotify and many others handle auto-updates upon startup.. be (even more) awesome..
When we can go back to having birthday parties with family and friends, I want to be able to talk (nay, BOAST) about the Affinity suite and the cool software you guys make..
.. because I love what you're doing ❤️
TL;DR: not having auto-update on startup sucks; I don't want your awesome software to suck.