I empathise with the tight connections - I used to occasionally travel from Westbury or Trowbridge to Aberystwyth, and had a 5 minute connection at Newport - and about a 7 minute connection at Shrewsbury. I usually had some luggage and the Holyhead train would usually arrive on Platform 3 at Shrewsbury, due to Platform 4 already being occupied.
After a couple of times of missed connections, I gave up and travelled an hour earlier, giving myself half an hour at Newport and Shrewsbury which was a lot better - this was using flexible tickets though, which weren’t too badly priced on this route at the time.