How can I maximize my gains?

[twra]

I just started my gym journey abt a week ago, I've been going as heavy as I can in all my exercises, going to failure, thn dropping the weight down, to failure again- repeating this process till there's no more weight left.
^ This is my one set.

I then move onto the next exercise. I start on compound movements (largest muscle groups), to the smaller muscle groups.

Is this the best way to train scientifically?

I'm not sure because I just saw from a source that one set to failure is better than drop setting to failure, or multiple sets to failure.

My goals are overall fitness (strength gains, endurance gains, cardiovascular gains, mobility etc.)

I will incorporate H.I.I.T, long distance running, and swimming eventually.

Anybody know anything abt the best method to train? Please drop sources too, if you have