I did the trans fluid change on my 2019 E300 / W213 back in OCT 2023 - car is still going strong. As noted the trans filter is integrated into the trans fluid pan.

there is a special tool that enables you to drain the old fluid out / fill the pan with new fluid / and fill the fluid till it is full - the fluid will overflow and excell fluid will drain out.

you need a pump to fill the fluid - Amazon has several models... also need a infrared temp sensor to measure correct fluid temp [39C] / think I bought 10L of fluid cause I also changed the torque converter fluid // need a good selection of Torx need a shallow /low profile T10 / I got a T10 wrench /

One of my unforcasted issues was supporting the transmission when I had to remove the trans support bracket - to permit removing a couple of pan torx... I used a bottle jack with wood chocks

again - You tube is your friend

you tube has several excelllent DIY videos..