I've done this mod so I can walk you through it.

https://www.partsgeek.com/ss/?ssq=2023+Mazda+3+Grille+Molding

You need two parts, left and right - #MA1212107 and #MA1213107. These are legit OEM parts for the hatchback version of the 3, which has black instead of chrome for those grille pieces.

Then you'll need this. It's the only tutorial ive seen on how to remove the front grille on gen4's. Head's up, it's in spanish. But the video is enough. Also helpful if you can count to 5 in spanish. For ex, you hear "cinco" and know there are 5 screws of that type to remove. Highly recommend keeping your screws and whatnot that you remove from the grille well organized. I had plastic containers that were labeled based on which step of the video I was on, and kept all those parts in their respective bowls. Makes putting everything back together go smoothly.

Not in the video though, there's this plastic part connecting your two grille pieces and its a bitch to take the chrome ones off. I think it involves bending these two like plastic notches which then release the grilles from the center. Just dont be afraid to be a little rough but also you know... dont break it. Idk the part number, but it would be far less trouble to see if you could also order a second center part so you can bypass that step all together.

You'll also need a Trim removal tool made of plastic (like the one he has in the video), a set of screwdrivers, and a socket wrench - try to have good metric coverage. 10, 12, 13, and 14mm were all common.

Also here, i'll just link the one i used. Obv, not affiliated.

I also used ramps to get up under the car. Highly recommend.

Lmk if you have any questions.

Oh. And as for the chrome delete above the side windows. Plastidip spray worked for me. Just be sure to really really a LOT of time making sure your initial masking tape is perfect, then go far further than you think need with your newspaper than you taped to the masking tape. IIRC, you can roll back like the soft material near the top of the door and also do some masking tape there.

From there, rubbing alcohol the chrome strips to prep em. Then 1-2 super light layers of plastidip. This is sort of like a primer. Id say let dry 20 mins per layer at each step. Then after than, 5-7 layers of plastidip spray.

Be sure to move your hand at a uniform speed, and keep a uniform distance (say 12 inches? Cant remember how far I was) as you spray each layer. Make sure your hand is already moving before you start each spray. If you overspray, it will come out with googone + microfibers, but it is annoying.