The originally created .sf2 file had included two drum kits. So I reduced it to one drum kit and it's now at 11 MB. So, I could upload to the polyphone storage. I tried to create a topic also in their forum but wasn't successful on this. I hate forums that won't act normally as usual and insted are wasting my time.
However, this is the link to download:
https://www.polyphone-soundfonts.com/do ... RydW0ta2l0