Does it tell you why Windows 11 won't run? It may just be that you need a motherboard update.
Everyone will tell you that you need to upgrade to continue to get free security updates. Whether you need those security updates really depends on what you're doing; if your PC sits behind a home router that does address translation and has upnp turned off and all you do is browse the web from an updated browser without opening randomly downloaded files then you're fairly safe. Possibly safer than you would be with Windows 11 continually downloading new adverts and all the risks that entails.
If that is all.you do then you're better off switching to Linux anyway and not having this problem or Microsoft spying on you.