Optimizing Report reaching data limit

I think that there is an easy answer here.  Go to the table hoe p[age and under the old style green button and then More ... use the option to Copy Table (with data).  Then decide where your cut off will be for old records. Let's say you decide to Archive out from 2021 and older.  So in the archive table you would delete everything after 2021, so run a report starting Jan 1 2022  and delete those from the Archive.

The make a report link field on the PT record or even a relationship from Appointment back to Patients based on he existing [Related Patient] field in the Archive table.

 Then put that Report Link Link field as an embedded report on your patient record and you can use a form rule based on a summary checkbox field as to whether there are any archive records to decide whether to show the report link of archived appointments.

Once you are totally satisfied that you have safely archived out a particular number of years and you are running out of space on your main table then be brave and run a report of the records that you want to delete off your main appointments table and then delete them.