A tray of carrots does not need to look machine-cut. It does need the thickest pieces to cook before the thinnest ones burn.
Look at thickness rather than length. A long, slim carrot baton may cook at a similar pace to a shorter piece of the same thickness, while one chunky end remains firm. Split the large sections again and leave small ones alone.
When combining vegetables, account for their different cooking needs. Dense potatoes may need a head start before peppers or courgettes join the tray. You can also use separate trays and bring everything together afterward.
The point of knife work is a meal with the texture you want. If making tiny pieces is tiring or uncomfortable, choose a dish that suits larger cuts and a longer cooking time. A sensible method is more valuable than decorative precision.