I didn't see this included in CastingEssentials or HLAE or similar already so here you go.
Now you can HLAE pub sniper clips!
https://github.com/mundungus443/SniperPOV/

EDIT: SOLVED BY ME

Currently, when playing back a POV demo of sniper, zooming in will cause the playermodel to disappear. This is a relatively niche issue, and I am not currently aware of a fix. If anyone knows of an existing fix for this, I would greatly appreciate it. If one does not exist, I'm offering 10 keys for a modification to fix it, preferably custom folder addon, w/ source code.

Specifically, the fix should make the sniper's playermodel and cosmetics drawn when zoomed in, so the builtin thirdperson command, HLAE, etc. will show them.

Relevant code sections:
Player nodraw:
https://github.com/lua9520/source-engine-2018-hl2_src/blob/3bf9df6b2785fa6d951086978a3e66f49427166a/game/client/tf/c_tf_player.cpp#L8397

Hats nodraw:
https://github.com/lua9520/source-engine-2018-hl2_src/blob/3bf9df6b2785fa6d951086978a3e66f49427166a/game/shared/tf/tf_item_wearable.cpp#L326

Thank you!

sorry for super late reply, it's bound to volume and media prev/next if pressed. Also undo/redo with modifier key

If it's still an issue, try binding a key to increase and then decrease your gamma. For example when I press tab, mouse3 or change class I have my binds run

mat_monitorgamma 1.799; mat_monitorgamma 1.8

and my scoreboard habit ends up mostly fixing it.

https://i.imgur.com/5LJHeg2.jpg

https://i.imgur.com/4FWshvP.jpeg

cajal 45% with brass plate, plate foam, and gateron ink blacks, lubed with krytox 205g0
caps are dsa bounty hunter sr.

I also have a KBD67 Lite R2 on the way, planning to build that with Zealios or T1s