Logseq can be launched as a desktop app and in a web browser and has both iOS and Android apps. Official sync is a paid feature but there are other options (e.g. Syncthing).
Second (or third?) Logseq. Bit of a learning curve, at least for me and overall it suits me much better than Standard Notes, which I was using previously. Standard Notes is now way overpriced compared to what it initially was, so great timing as well. One gripe I have with Logseq is you are unable to export queries as a page or text doc. It definitely has its quirks, though overall it's great. And if anyone wants to share how they organise pages, tags, etc. feel free!