I'm not sure how much each of these suggestions have already been discussed, but I had compiled some of my thoughts on the in-match experience into a few annotated screenshots. Keep in mind I am playing at a windowed resolution close to 3440x1440, so some of my suggestions are going to be tailored towards players with more screen real estate.
It would be great if we could customize the "Match Stats" box on the left. We do have customizability on the "Match Stats" on the touchline tablet, but the whole top section feels redundant since we can already customize on the touchline tablet. I would love to see more customization on the left side since there is so much extra space left over.
I've also noticed a few names in the "The Dugout" box that are missing hyperlinks.
Going back to the "The Dugout" box, it would be nice to be able to scroll through past notifications. Right now it seems to disappear after about 10-15 minutes in the match. I understand that some things become irrelevant if, for example, the player in question has been subbed off. But I feel like some things disappear a bit too quickly, especially when playing at higher speeds.
When entering the "Tactics" page, I noticed a column called "Status," but it is not clear what it does. You can see nothing in that column for each player line.
I was also unable to add a column to see total number of assists in this match. I was only able to make a column for total number of assists this season. Perhaps adding a "Current Match" section when customizing this view would be nice.
On the tactics page, the icons for "Body Language" are not very clear. Right now, there are only three preset icons that generally indicate a Positive, Neutral, or Negative body language. However, this is inconsistent with the "Sharpness" and "Condition" icons which both have more colors.
The "Notable Events" box is not very detailed. Because the timeline was removed in 2021 (the ability to jump to any minute and second on the clock), we are now presented with far less detail when watching a match. Right now, the "Notable Events" box only shows goals, missed penalties, offside goals, and cards. I think this should also include other significant events such as "good" chances (perhaps reserved for shots that add a certain amount of xG), substitutions, and goals called back for handball/fouls.
In the past, a player with a slight injury had an orange cross (as you can see in the "The Dugout" box and on the bottom bar. However, this is not reflected "Team stats" pane on the Touchline Tablet
Speaking of the bottom bar, it definitely does not scale well. I know this screenshot is a bit small, but you can see massive empty spaces between players. It is very difficult to, at a glance, see the different icons on this bar.
Continuing to look at the bottom bar, the "Team Stats" box does not obviously indicate when a player has been subbed off. You really can only tell if you check to see if a player has a rating AND has a grayed out name on the Touchline Tablet OR you have to look for the very small icon int he top right corner of the player's box on the bottom bar. Having some sort of indication on the touchline tablet that a player was subbed off (and perhaps the time they were subbed off, just like in FM20) or putting this information on the "Notable Events" section on the left side of the screen would make this information easier to find.
The screenshots are not quite that large because of the size limit on the forum, so here is a link to larger photos. https://imgur.com/a/DjfBMLA
Thanks for reading some of my feedback. I am happy to expand more upon any of the items I have mentioned above.