My Coffee Procedure

So my puck prep and coffee procedure goes as follows:

1. Water: Evian
2. i let the portafilter heat while the zuriga heats itself. then i wipe the excess water out of it.
3. i put the portafilter into the grinder and get exact 18g due to the gbw. its a double basket (17-20g)
4. i tap all the sides to get it evenly distributed
5. i tap it lightly verticaly on my tamping mat
6. i tamp it and try to get even pressure( got decent at it, seems level the last 20 times) not sure tho if its enough pressure/too low/Consistant? but i heared that its not that important...
7. putting the portafilter into the machine and try to reach 24-27sec while having 1:2 ratio. with my timemore mini

-> What i notice is that after the extraction the puck has slight impression in the middle from my Shower and the shower is slightly dirty, i always get some whater outta there and clean it. but i think its because of the blooming of the puck and not because the puck is too full.. since its made for up to 20g. but could be a problem.
i also used naked portafilter, extraction looks kinda decent i think.

-> im not sure if i like the coffee in general, i never tasted an ideal shot... my next step would be going to a lokale coffee roaster to try in advance a coffee that i like and see if i can get there.