Samsung Galaxy S23 Plus and Simple Choice Unlimited plan

I have had my Samsung Galaxy S23 Plus for a year now.  Since the beginning, I have had numerous issues of:

1. not receiving text messages, both with non T-Mobile users and T-Mobile users.
2. on occasion not being able to send a text messages
3. text or photo gets sent 5 or 6 times to a non-tmobile user, while on my end it shows that message has failed to send

I have done numerous trouble shooting sessions with T-Mobile and Samsung.  Switched from Google messaging to Samsung messaging.  Switched out physical SIM card once last year, and then most recently got an ESIM.  I also got a replacement phone about 2 weeks ago.  Nothing has helped the text messaging issue.  When I look at network connections for my phone, it shows 5G and 2G network options.

My question is:

Does the fact that I have an older Simple Choice Unlimited plan have any effect on my current 5G cell phone?  When I try to click on plan details, the Simple Choice plan talks about 4G unlimited.  No where in the plan description does it talk about 5G.  In other words, do I need to switch to an updated phone plan in order to get this text messaging issue resolved?  

Or is the real issue network congestion?

Anyone else have this issue?