Effective ways to upgrade a Music Hall MMF 2.2


I am researching ways to upgrade a Music Hall MMF 2.2 and would like to get some advice.

1. Change the platter to an acrylic one.
2. Add a Soundbox - this is intended to be for automating changing the speed from 33 to 45 with a click - why are folks indicating this would improve sound quality? Confused about that aspect.
3. Changing the cartridge - how high can I go for this type of turntable and arm? Will get a different counter weight if required.
4. Should I consider changing the arm? When do these things become ineffective? I.e., what role does the table itself play in the quality of the sound?
5. I would like to upgrade my phono stage from the NAD PP2 that I have. Would a Project Tube Box make a difference?

Thoughts welcome.
shugho
Thank you for your advice. It all makes sense. I was also thinking that buying a new cartridge that I can later transfer to a new turntable makes a lot of sense. Also, the mat and the acrylic platter sound like reasonable upgrades that will provide the right ROI. I will let you know how things go. Thanks again.
Best advice is Viridian and the Nagoka MP-150 .
ALL any sensible person would ever need.
Which leaves me out .
Schubert, Sorry - what is a Viridian? I am not finding it in my web searches. That is the second recommendation for a Nagaoka MP 150 which intrigues me. I was considering a Ortofon 2M Blue or a Denon DL-110 based upon advice from a dealer and this is in the same price range - do you think it is a better cartridge than these or just different?
We might not be 100% certain what a Viridian is, but in at least one manifestation he or she is an often helpful poster to various audio threads - as in the 2nd response to your query.
#3 and #5

Upgrade the cart and phono pre.

Many choices out there and I'm not sure about your budget.

My advice, Ortofon 2M Red/Bellari VP130 tube MM phono
pre for about $350.00 all together will bring new life to your 2.2

Money to spare, DV10x5/DV P-75 (used) for about $800.00

Again, many options out there, just my opinion.