Undefined index and undefvined variable error

We have been noticing a series of errors at the editor end and also during draft sessions; which probably clogs the database and causes a huge memory leak and disrupts regular server operation often; only resolved by force killing the server.

wp config details

‘WP_MEMORY_LIMIT’, ‘256M; ‘AUTOSAVE_INTERVAL’, 160; max_execution time 500

Attached a sample screenshot for your reference, kindly look through

Thanks
PFA
https://drive.google.com/file/d/1Phlm-M5tfar_BSkMRqnbFCLTFc89opfa/view?usp=sharing
https://ww.wp.xz.cn/support/topic/too-many-datadabse-connections-upper-ceiling-mysql/

The page I need help with: [log in to see the link]