Since you're just using it as an AP, not as a router, the CPU will probably be fine, and it has more than enough RAM. I'm sure the wireless component of the chipset is good enough as well. I found ...

Starlink has started notifying customers that one of its oldest routers is nearing the end of official support. If your setup dates back to Starlink’s early rollout in 2020, you may already qualify ...

Did you match the mac address of theh old router? It's possible your isp does mac filtering and thus it's not working. So look for a setting on mac address or call you isp to see if they can update ...