Memory usage and database accesses have increased dramatically

Since updating to version 2.3.21, memory usage has increased by approximately 1000 MB, and the number of database accesses has also risen dramatically. As a result, my website is extremely slow and no longer runs because it exceeds the server limits. Everything was fine in version 2.3.19. To my knowledge, nothing else has changed in the WordPress installation! Can you check this. Thanks in advanced