I forgot to add the pics of the bottom cabinets. I know Im using knobs on the top. Im playing with various colors to choose from, but I can decide on that after choosing for the lower. Thanks in advance!

Use the same size for all pulls.

Since your cabinets vary from 12" to 38", a pull that will fit the 12" cabinet or drawer will look puny on the 38" cabinet/drawer. A pull that will look good on the 38" cabinet/drawer won't fit the 12" cabinet/drawer. The reason the manufacturers make different size pulls is to fit different size cabinets and drawers. The 1/3 rule of thumb is a good one for a nice balance aesthetically. If you are undecided about the size of a pull, make aluminum foil templates of the sizes you are looking at, and hold them up against the cabinets/drawers to see which size looks good to you.

Do not "double up" on the larger drawers. As you said, it can cause issues. People tend to pull on just one which can cause racking of the drawer, or, the pull being used the most on one side loosens over time.

Use 6" pulls on everything and double them up for the very large drawers.

The kitchen in my previous home had the arrangement that @Sabrina Alfin Interiors mentioned. It was put in 22 years ago. Time for a change to more current. I recommend single pulls. The 38” drawer you have is commonly found, and a 12” pull that will look good with it is commonly found.

I would do two sizes of pulls.

I also dislike double pulls on one drawer. To me, it looks cluttered and old fashioned!

I might be seeing 2 clear knobs on top. ?

Do you want those acrylic/metal handles for the bottom? if the open area seems to 'need' a bit more.

Use a combination of different length pulls to be in proportion to the drawer size. Don’t do knobs on the doors. They will look unimpressive (and old fashioned) next to pulls on drawers. The only place I think knobs really work in good balance is on short ceiling level cabinetry stacked on top of other cabinets.

Not quite, but these details remind me of cabinet's edges, and of style of knobs - are they wood?

https://www.amazon.com/Asidrama-Brushed-Antique-Kitchen-Hardware/dp/B09SWCCLXD/ref=sr_1_182_sspa

Like a simple knob, like frig handle - this?

https://www.amazon.com/Alzassbg-AL3502ORB-Centers-Hardware-Contemporary/dp/B089PVQ32F?ref_=ast_sto_dp&th=1

Amerock's metal design seems traditional, and not smooth/flat... just something different.

https://www.build.com/amerock-bp36655/s1431541?uid=4297832&searchId=FZJtPyi6FA

Beautiful cabinets. I understand your concern. Consider classic cup pulls and simple knobs in the same finish, which would be my first choice. IMHO bars are too contemporary for your cabinets.

Brushed Nickel - here's a combination of cups, bars and pulls

Hi - we had the same issue because we have different sized drawers on our lowers. What I did was make the decision to do uppers in all knobs and then I purchased two different sizes of pulls and varied the pulls based on the drawers. I loved the idea of making mock pulls with foil. You can do this!!!