Starship is likely to do something different with GEO and further missions. Payload to LEO is just so huge and cheap compared to anything else that it will likely do a kickstage or just larger satellite thrusters. Falcon Heavy can only send 26.7t to GTO fully expended and doesn't have the volume to handle too large of a payload. Starship is 100t and likely more to LEO while fully reused with a massive volume as well. Elon himself doesn't care about Falcon Heavy, so I expect SpaceX to find ways to push everything away from FH as soon as possible.

Also keep in mind that once Starship is able to fly and be recovered reliably, it becomes more beneficial for SpaceX to fly Starship more often. A fully reusable Starship should be nearly 1/5th to 1/10th the cost to fly as a Falcon 9, and well past 1/10th to cost of Falcon Heavy.