the problem with using a pi 400

I have been using a Raspberry Pi 400 as my main pc for a few days now, and I ran to a few issues one of the problems it seems to have a hard time running Firefox or any modern web browsers It also seems to struggle with email clients like thunderbird I tried everything I could to fix this even overclocking it to 2.3 GHZ i guess i have to resort to using mutt and other text based clients I'm also very limited on space the 64GB micro SD card just doesn't cut it however that will change soon because i just recently ordered a Kingston 1TB USB SSD drive which should be in the mail 3 days from now if all gose well