Is using A/C sealer refridgerant really that bad?

1998 Mustang GT

I know the compressor works after manually jumping it using the clutch switch. Even on hot days I can still feel some cool air when its on max ac but it’s not enough. I have tried recharging it normally but it didn’t make a differance which is what lead me to believe that I have a leak somewhere. Is using sealant while recharging it again detrimental? Should I try using the uv dye trick? thank you