Wow, if there ever was a thread for me!

I have done it both ways! I left a great career in computer graphics to go through a long journey through the aerospace and energy sectors, and now I am on a return trip to CG.

During this process, I
-Built my own machine shop
-Worked at <Cutting edge aerospace company>
-Built up an entire material science research lab
-Learned how to manage an amazing team
-Got really into machining, manufacturing and facilities

Whoever said that most of your time as a mechanical engineer is spent buying stuff and sorting through boxes/messing with supply chain/inspection is right. Your tolerance for cardboard boxes must be very high to do physical engineering.

Machining is really fun and soothing at times, but once you have learned it enough, you realize that Xometry and Protolabs and Front Panel Express and SendCutSend are just... better than you. One thing I learned is that machining was a fun hobby, but it is not fun to have it as a part of another hobby. It is always cheaper and quicker to outsource that labor. I want to make a telescope eyepiece tray, and I know I can design it and find a makerspace with a laser cutter and make it myself, but I am probably just going to order it from FPE so it will show up to my door, done, without any painting etc. I almost bought a mini lathe again (I sold off my first machine shop), but I realized that the thing I was thinking of making with it (tiny model biprop rocket engines) were hard to make and if I did pick up that hobby, I would rather just pay my buddy to make it on his superlathe and spend that time on designing the stuff he would make.

Another huge part of physical engineering is relationship management. You need to have someone to do everything. You need a good relationship with your sputter coater, with your weld shop, with your general contractor.

There is not actually that much senior level design engineering work to be done. Usually design work is done by about 10% of the org, and the rest of the org does support activities for that. There is nothing wrong with that, and there is plenty of interesting work in the support activities (I made a career of doing those activities)

I did all this with no formal education in the sector. I spent a lot of time in machine shops, reading books, going to rocket launches, networking. John Carmack was my principal inspiration (I met him at a tiny rocket conference once)

As far as comp is concerned, it is decent but not MANG like. I got lucky at <Aerospace place> and got in early enough that my TC was actually pretty solid due to relatively large share grant. I did have 5 room mates when I worked there because the cash level was low. My first aerospace job was paying me the same salary as an In N Out employee makes now. (They were taking a chance on me, so no hard feelings at all, it was a privilege to make that sacrifice!). You can make a living as a physical engineer, but you might not make a killing.

So, if you are committed to a huge downlevel for 5 years, you can have some fun adventures!

PS: Knowing how to write python is a superpower in these fields, I would guess than less than 10% of mechEs at the senior level know how to code. I imagine new grads know how to code now. I always was able to sneak a quick victory in various projects because I could write some hack code that did something tedious quickly.

PPS: Respect. Your. Technicians. Respect them. Treat them as partners. Do right by them. Value their feedback. Do their work from time to time. Pay attention when they speak, and act on what they say. Same goes for your machinists, material handlers, buyers, etc.