At 73, small rises are now hills, looking to change my chainring from 46-41 to 46-?? and the cogs are 14,17,22,27,34….will I need to modify my chain length?

Thanks
Halfmile

Hard to say. Chain length is a function of gearing, derailleur capacity, and chainstay length. If your derailleur can wrap the current length with a smaller inner ring, no worries (check on small-small combination). If it can't fully wrap the chain on small-small, take a link or two out, check small-small again for wrap, if good, check large-large to be sure that you're not running the chain too short. If it is too short on large-large after cutting a link, you'll need a rear derailleur with more wrap capacity.

46-34 will be the chain length primary control

I saw long ago 40t Dura Ace. Not sure on smaller

If your BCD is 130mm, 39T chainrings are available.

I’d run a different crank with a smaller bcd, so that you can run a 50/34 or a 46/30

I put an early DA crank on my PX10 and later put a 39 and a 45 on it to replace the stock rings but I'd want a triple these days.