I can only speculate, but you asked for ideas, so I’ll try my best. Don’t feel obliged to reply, and take it all with a hefty amount of salt.
I recently expressed to @MarkKO in another topic that just because we don’t actively perceive something as impacting us doesn’t mean we aren’t impacted,
And with respect to that, and also relevant in the context of why the above was ever put into words is that even though some among us might be fortunate enough to feel,
the reality is still that we have an ongoing global pandemic,
and that might affect your emotional state without you noticing. I don’t know what streams of consciousness you take part in while you are online, but I’m seeing people online that normally wouldn’t be and mostly everyone is expressing their discontent, worry, and angst publically. It doesn’t have to affect a person, but I for one am affected by their emotional state. And those are just tiny blips on my radar, friends losing jobs etcetera makes far bigger waves.
Further on the same tangent with regards to things that may have an emotional cost or toll, regardless of you actively perceiving it is that I’d be exhausted if I had to deal with the tone that some people have when they post in your log. Either that doesn’t affect you at all, it directly affects you (but then you’d know if that was the issue) or it’s something you subconsciously parry, and if it’s the latter well…
Then we have the physical health/mental health bit. As @dagill2 mentioned, hormone levels can certainly be a culprit.
This might have a relationship with your training as well. I know it wasn’t super long ago you deloaded, however, I cannot recall if you deloaded intensity wise or volume-wise. But given my perception of how you treat your rest days, I’m not sure your body was given the decrease in training stress that it needed. It’s fine to go in for a heavy top-set but that should be adequate during a deload.
Training, even though it makes us feel good, is a stressor.
I like what Dr. Jade Teta has written on SHMEC (sleep, hunger, mood, energy, cravings). When I’m under-recovering I see problems with all of those. Your sleep rarely seems affected by anything other than caffeine but sounds like a few of those “boxes” are ticked off potentially indicating an issue with your exercise/eating/recovery-balance. I really hate to belabor the point, especially after acknowledging that I myself would be exhausted with some of the input you are the receiving party to but there is a pattern with people telling you that you are doing too much.
And how do hormones and training relate to one another. This is not my area of expertise (nor is mental health) but looking at your training sessions I can’t help but imagine you being at risk of having to release a lot of cortisol to mobilise glycogen stored in your muscles. And what happens then is something referred to as the pregnenolone steal. Cortisol and testosterone are both made from pregnenolone, but if you use all of your pregnenolone to make cortisol that leaves you with very little left to make testosterone.
I’m not sure what your dietary habits are around training nowadays but I know at one point you’d go for a really long walk after having done a monster session. So I could see how you might end up using all the glycogen you had available for use without mobilising cortisol to get more glycogen.
I’ve shared information about carbohydrate needs around different types of training before (original author CT),
and you very often fall into case 4.
And sometimes we are just sad. Feeling depressed is fortunately not the same as being clinically depressed.