I like k-9 mail because it has everything and it is reliable. but most of all i like it because i can transfer it to my external microSD card. apps like tiktok (is on external, thank god), youtube, ebay (external), amazon, gmail app, FIREFOX especially produce huge amount of data. on my 32 gb smartphone i have to delete data weekly. i have calculated with another 128 gb smartphone (which doesn’t have microSD slot sadly, i produce 1-7 gigabyte per week by just consuming streams (it’s good for lowering stress). i have to delete the cached data otherwise i can’t use the smartphones properly. when the times come where cheap smartphones have 512 gb of storage (i call it rom, compared to ram which should be now minium 12 gb, 8 gb is to low), i will not need a microSD card becaue i delete cached data only once per year.
my question is: does anybody know a browser, which can be transferred to external microSD card? even fennec doesn’t support it anymore 
microsd cards are definitely not slow for me.