[ahelwer]

There's no product you can buy that will make you a better software engineer other than time off from work so you can explore, learn, and develop according to your own interests.

[verdverm]

Came here to say the same.

Money won't buy you skills, but it can afford you the time and space to put in the effort

The best way to upskill is to build while learning. Merely consuming information will not typically help.

[gammadist]

Would “cultivate an interest or hobby to avoid burnout” be an accurate summary of your comment?

[ahelwer]

No, it would not. You avoid burnout by not having a full-time job in addition to whatever personal development you are pursuing.