I found that (for me !) it was less useful to invest in learning to do new things, as opposed to investing in being more efficient and / or having my work time more pleasant.
Make your work feel like pleasure and there is no limit to what you can achieve. So maybe don't only think "what can I be better at ?" but also "how can my life be better while I work ?".
Software:
A proper training session with a high level debugger for a language I wasn't used to, debuggers often have esoteric interface and "hidden" features, but learning to use them comfortably will make your life so much easier and pleasant.
Buying a license for a good IDE (in my case, intellij). I use vs code 70% of my time but when I need to work on more complex pieces of code or debugging it just change your life.
Hardware:
Buying a proper "high quality" laptop, notably the screen (real matte screen because screw glares, and 2k/3k/4k resolution because you look at text all day so crystal clear font rendering matters a lot).
A great chair with proper support because my back hurting at the end of every day is not ok.
A switchable sitting / standing desk ( https://www.autonomous.ai/product/standing-desk ).
Quality noise cancelling headphones (Bose QC 35).
Make your work feel like pleasure and there is no limit to what you can achieve. So maybe don't only think "what can I be better at ?" but also "how can my life be better while I work ?".
Software:
A proper training session with a high level debugger for a language I wasn't used to, debuggers often have esoteric interface and "hidden" features, but learning to use them comfortably will make your life so much easier and pleasant.
Buying a license for a good IDE (in my case, intellij). I use vs code 70% of my time but when I need to work on more complex pieces of code or debugging it just change your life.
Hardware:
Buying a proper "high quality" laptop, notably the screen (real matte screen because screw glares, and 2k/3k/4k resolution because you look at text all day so crystal clear font rendering matters a lot).
A great chair with proper support because my back hurting at the end of every day is not ok.
A switchable sitting / standing desk ( https://www.autonomous.ai/product/standing-desk ).
Quality noise cancelling headphones (Bose QC 35).