There is no need to have 3 clubs the same loft. A lot of people have trouble hitting a 3 iron so they switch to the 3 hybrid which is much easier to hit. If you can hit your 3 iron keep it. It's just nice to have alternatives for your game.

Fay, Welcome back to golf! It seems that for your re-entry that you should practice with the clubs you are familiar with and then test the hybrid to see the difference. Irons are easy to use for various challenges; you can hit a lay up. chop through rough grass, and even putt with a 2 or 3 iron. The hybrid can be used in the rough or fairway so it does dual jobs. Just play and enjoy and you will soon know which club is best for your skill.
Spartawo…

Your three 21 degree clubs will all play differently. First or all, the three iron will be hardest to hit, and will go the shortest and lowest. The hybrid will fly lower than a 7 wood, but is easy to hit from many lies. Finally, the seven wood will be easiest to hit, and will go the highest and furthest, so there's no reason not to use it.