Installment sale

https://www.irs.gov/publications/p537#en_US_2023_publink1000221601

1.  you figure out your Gross profit percentage.  (gross profit) / contract price = x%

2. for the principal you received for the year,  x% * principal is subject to capital gain tax. 

3. the interest you received for the year is taxed under ordinary income. 

Next year, repeat  2 and 3.