The rep from B&H suggested a good computer for me. Everything about the computer is excellent but the processor seems so outdated. The processor is
2.9 GHz Intel Core i7 8-Core (10th Gen)
Is that good enough or too old to purchase at this point?
Its not so old and you probably get a better price for it because of it. If everything else suits your needs then I don’t think this should stop you
You think it will be enough to handle Illustrator, Photoshop, and Indesign at the same time together with my filter? What about large format files, I often get messages like could not perform the task because the scratch disks are full. Do you think I can work with files in photoshop like 80inx130in?
I think for regular graphics it should be find. For video and motion graphics always go as high as you can… and even that will eventually not be enough 
Agreed that it should be fine, I actually worked on an older processor than that for a long time with no problems running the graphic design programs. B and H has always had very knowledgable customer service when I have dealt with them, so I generally trust what they said and find them to be reliable and honest, just my personal experience.
Is a processor something that can be updated at a later time?
I would not have thought so
Laptops are not normally upgradeable but desktops are generally upgradeable but are limited to the latest version the motherboard can take.
If the scratch disk is full it’s probably because there’s too much storage there, nothing to do with the computer…
Just had an issue with scratch disks myself, you have to either delete a lot of photoshop files or upgrade your computers internal hard drive. (You can also use an external hard drive to save your files to)
I’m still on my computer question.
I have these 2 options, any thoughts?
(https://www.bhphotovideo.com/c/product/1609507-REG/hp_2x3n2ut_aba_z2_g5_twr_i9.html)
add 8gb graphics card. will be total of about 2800.00
or
upgrade ram to 32gb total about $1950