My Galaxy S5 seems to be the LTE International version codenamed: klte. Most of the ROM I have found doesn’t support the g900m version, only g900f. I’m not sure if /e/ does the same.
Yes, /e/ OS supports the device version SM-G900M.
Please have a look at /e/ documentation bottom right > /e/ OS Information > Models Supported
There are numerous variations or versions of the Samsung Galaxy S5 …
SM-G900A(Z) SM-G900F 16 GB SM-G900F 32 GB SM-G900FQ SM-G900H SM-G900i SM-G900K SM-G900L SM-G900M SM-G900P SM-G900R4 SM-G900R7 SM-G900S SM-G900T SM-G900V SM-G900W8 SM-G900FD SM-G900MD SM-S902L
… with different specifications. The differences are small, and usually relate to the LTE frequencies and bands.
/e/ for klte dev (Pie) runs fine on the S5. You will be pleased.