What rating system is a better determinant of skill level Lichess or Chess.com?

I recently started playing on Lichess and reached 1600 within a few days. However I am unable to break out of the 800s on Chess.com. What is my true skill level?

White to move

I finally got there.

Omg! Finally broke through the 1000 rating barrier in chess today. 🎉 It's been a thrilling journey of strategy, tactics and checkmates. Here's to many more victories ahead. ♟️🥹

Why is losing my bishop the best move? Is it just because I have a winning position afterwards?

My friend found this in a BULLET game!

THE SAME FREE TRIAL CHESS PUZZLES I DO DAILY HAVE LED ME TO THIS MOMENT

What does "Tr.T." mean in the third column on the fide ratings chart?

Can someone explain why is this a brilliant?

Black to Move, Can You Find M5?

Found this mate in 5 in a recent game.

Pinned pieces pinning pieces for the win

Almost missed a mate in 3