Spent years repairing old industrial gear, so let me explain those wiggly traces you see on boards from the 80s and 90s. They were drawn by hand. Literally. The layout person taped black crepe tape onto big sheets of mylar at 2x or 4x scale, and cutting curved runs with a sharp blade was often faster than making neat right angles. Every bend was a seperate little patch of tape, so curves saved time.
The other reason is that 90-degree corners were genuinely frowned upon back then. Old etching processes coud underetch the inside of a sharp corner and leave a sliver of copper, so the rule was 45 degrees or curves. Your straight-traces-with-right-angle-bends board from the same era is actualy the odd one for its time. If you ever need to trace out one of these boards, here is what worked for me. Put the board on a lightbox or hold it up to a window so the copper shows thru, then follow one net at a time with a colored pencil on a photocopy. Curves are friendlier than they look, they almost always take the shortest path around an obstacle.
Last tip, count the solder joints on the underside before desoldering anything. Hand-assembled boards often have reworked joints that never matched the drawing, and that will send you chasing ghosts for hours.