Increasing performance of cache_form on high traffic sites I am noticing a significant performance increase in my load testing when this table is small, but due to a large traffic site this is growing very quickly.

I have read that it is not a good idea to move this into an "in memory" cache like redis or memcached but can this be moved to a noSQL database for example?

My issue is that even with frequent clearing of old records the performance is struggling and my main solution is to take the database offline and optimize the table to reduce the physical size of the table in MariaDB.
Checkout https://www.drupal.org/project/apdqc if you're on D7; this is my config for it in the settings.php file.

$conf['apdqc_cache_default_compress'] = 2;
$conf['apdqc_cache_compression_level_cache_form'] = 3;