Will a slow drain lead to drain flies

[RT1001]

Ok, first post so here it goes:

Our shower drain is slow. An enzymatic cleaner typically clears up the issue, at least for a few weeks. Does anyone know if living with a slow drain for periods of time could present an issue for drain fly infestations? Seems like online articles say so: https://goodbyedrainflies.com/drain-fly-guide/

We have seen them in our basement...I suspect the internal water management system and sump pit are culprits.

The home is mid 40's if it matters.

Thanks!