I had the V30 and found the Nextdrive Spectra X (dongle dac) to outperform it slightly.
But just to make sure , did you use the v30 in the high impedance mode or not?
This would make a substantial difference.
There is no way to turn on high impedance mode on the v30 that i can see. All mentions of it say to buy a dongle to trick it and then plug into that, or to root the phone and do it via a software. You cant just flag it on and off as is. Apparently the v20 you could just by holding down the hifi dac icon. I listen to everything at 14-18 volume at most V30 and 2020's so its certainly not lacking in power.