The difference between the pe90 and LA4 are not that great when the pre90 works as intended. The following reviewer put them head-to-head.
Topping Pre90 + Ext90 Review - Pre-amp my Power-amp! (soundnews.net)
For me, I hated the fact that the pre90 worked well with only 2 of the amps I tried and was unusable for me with 4 or 5 others. It was a volume issue. The LA4 works with any amp and there are more needed features and robustness to the implementation and feel. I really wanted to like the pre90, but it failed.
If you like a bit of warmth, I highly recommend the CODA 07x. It is not as quiet as the pre90 or LA4 but not that far off. It has a tube-like sound that would appeal to more people. I gravitate more towards the LA4.
The Musetec 005 with the 07x works well but if your amp is warm and the speakers are warm then it maybe too much of a good thing. In such a situation I would change out one of the components to tone that warmth down.
I say this because the 005 was the only SS DAC that worked with my RAAL SR1a headphones when used with a 2-channel amp. It was also the best DAC by a mile for such a use case. The SR1a is extremely revealing and a bit bright. In comparison, my Benchmark DAC3B was a no go with the SR1a and 2-channel amp, too bright.