Low water pressure in kitchen faucet

So I recently installed a dishwasher, and ever since then my water pressure has been much worse in my kitchen faucet (only the kitchen faucet, both hot and cold) when I did my dishwasher install I noticed my shutoff valve for the hot water wasn't working, thinking this might be my problem I cut my copper pipe and replaced the old shutoff with a new sharkbite fitting, but I didn't really notice much of an improvement. I checked and cleaned the aerator, but that wasn't the issue (ran the tap without the aerator as well, pressure is still pretty pitiful)

Other than those two things I'm kind of at a loss to what my next step should be. ..Ideas anyone? Any help would be greatly appreciated!

Should have cleaned the sink first. Its only peanut butter! Haha

My guess is that something got loose, and has made it past the valve and is in the line before the aerator. I’ve seen a few of the sprayer on a hose faucet like that, that had a flow restrictor/limiter located where the hose attached to the faucet.

Check and see if any galvanized under the house, specifically in that area. One galvanized nipple can create low pressure. If you rule that out. And know everything is copper or something better. I'll bet it's in the shut off. Turn it off and on numerous times and see if the pressure goes back to normal. Might've grabbed some debris while it was off.

pull out spray hose and unthread sprayer there is a screen in there that sometimes gets clogged. turn water on without sprayer on hose and check pressure as well

Like Mike said.

Apologies for the delay writing back, life got a little hectic and this repair took a back seat for a bit, I've unscrewed the head and there is no other screen, the water pressure isn't any better with the head off either, any other ideas? I'll post a pic of the head off and what under the sink looks like, appreciate everyone who's taken the time to reply thus far!

disconnect the water supplies from the faucet use a new supply direct it into a bucket and see if you have pressure....do it on both hot and cold....

I removed the water supply line from underneath the sink, when I turn this on I get a very normal powerful stream, so I guess the issue has to be somewhere in the faucet

So the next step is to hook back up, and remove the cartridge and have someone hold a glass over it, and turn on the shutoff, and see how the flow is there.

Then keep following the pressure and flow until you find the blockage.

or you could try a wet/dry vac after the cartridge is out

at this point if faucet is new I would try to clean like Geofd said..if it is older just change faucet out.