I’ve tried flats many times and just can’t get them to work for me, but then I play punk and rock so in general not the right tools for the job. The only time they fitted well for me was in a band where we had 2 basses, I played the lower register with clean flats, Motown type lines, the other bass was higher register with driven rounds, like New Order. Worked well and if I ever play Motown or similar I’ll head back to flats as for me that style of music lends itself to the thud of flats.