AndroidOS does not support ExFAT or NTFS. However, we heard the feedback from users, and the LumeUI update that is currently rolling out includes the MyOS File Manager from ZTE which will read/write ExFAT. However, it won’t add ExFAT support to other Android applications. It will, however, if you choose, let you store movies larger than 4GB on your MicroSD card and transfer them back and forth with your Lume Pad 2’s internal storage so you can play them in LeiaPlayer.
You may also be able to use the NOVA Video Player MicroSD card workaround shared by @eazyedd2 but that hasn’t been tested with ExFAT.