Just to clarify this is intended to discuss turn lengths with combats of larger groups in game time, not table time.

As many of you know, a turn in 5e is 6 seconds as is a round. I'm concerned with round timing with larger parties and wanted some input from other DMs. Our party is 7 players, and they usually face large mobs due to action economy balancing, so we're often looking at around 14 or more turns per round.

I think this may introduce game breaking potential for 1 minute duration spells. At 6 seconds per round, we're looking at 10 rounds of 14 turns each, or 140 individual turns, that resolve before a 1 minute duration spell fades.

I think this makes a spell like faerie fire extremely powerful in large combats to the point of making it a game breaking ability, since it can stick around so much longer, and the combatant has to endure so many potential attacks between turns. One casting of the spell could give an entire side advantage against multiple enemy combatants and potentially kill anything that fails the save in one round. Multiply that by 10 rounds, and the spell is insanely strong.

I understand much of this is due to 5e not intended for such large combats, but for that reason I wanted to get thoughts on home brewing to slightly tame this. I was thinking of 10 second rounds to tame the length of those spells. Most combats are over in 3 or 4 rounds anyway, but it at least creates a realm of possibility that those spells end before combat is resolved or concentration is broken.

Alternatively, if I don't, I can see combats often being decided entirely on the backs of these abilities. Half the PCs fail the save? Good luck. I don't want to pull punches on my players or slaughter them because of how the rules are written, so I'd prefer a home brew rule that can tame this a bit.

Alternatively, I'm overthinking this since any combatant can attempt to break concentration.

Thoughts? Thanks!