Good luck with that. You may as well be asking for Windows XP support. KitKat hasn’t been maintained for nearly seven years! KitKat is not going to be capable of usng current security protocols or certificates.
KitKat is long past its use by date. It is time to put it to rest and move on to current and supported operating system.
What device is it? Sometimes you can extend lifetime by applying an alternative OS, e.g. LineageOS (which is based on official Android) which supports later Android versions.
I want to chime in to endorse the suggestion offered by @stphn with more than just a 'like" on his reply. Flashing a newer OS is the most sensible option for keeping a device that old in service.
I avoided such a suggestion in my reply only because it can be a daunting task for the uninitiated. The XDA forums are an excellent resource for such endeavors and are suitable for beginners and experts alike.
Why not simply download an old version of K-9 from apkmirror?
Plus what do you mean that you can’t log in without GPS enabled? If you mean Location then that’s not true - I have Location disabled on all my devices and K-9 works just fine.
Oh and FYI: yahoo, gmail or proton for example are email providers - what you are looking for is an email client