If for example you play a game that does not allow VPNs at all you can use split tunneling, but that will disable the kill switch so you can’t have any sensitive pages open in a browser while you are playing the game.
Some other VPNs have a socks proxy you can bind your browser to that acts as a second kill switch (among other benefits like less captchas). Proton has said they will never implement this because they believe it’s insecure Why Proton VPN does not offer a SOCKS5 proxy | Proton VPN. I don’t know all the technical details of the implementations on other services, but my understanding is that the proxy is connected to through the regular VPN connection so there is no unencrypted data like they claim in the article. In fact it adds another layer kind of like multi-hop.
I also think some other services have a kill switch that works with split tunneling.
I hope they consider some solution. At this point I’m thinking of subscribing to another VPN only for browsing and keep proton for torrenting.