Tips and tricks to keep Woocommerce running smoothly after a few years

I’d like to find out if those of you that have Woocommerce shops with large amounts of plugins/functionalities (eg 40+ plugins – feeds, automated mails, etc) have any particular optimization solutions besides the regular ones.

After being away from WordPress development for 3 years, I was faced with a situation in which database queries were really slow (postmeta table around 5million rows) and the solution was to add SQL indexes on all the columns in that postmeta table (not my solution, hosting provider did that).

I was wondering if this is something people often look into with regards to optimizing/speeding up their WordPress instances.

I was thinking that the WordPress installer which is setting up the database would set the columns indexes as efficient as possible.

Could it be that this is already not scaling up anymore?

Is this a common issue for medium-large setups?

Let me hear your thoughts, thanks!