Samsung tablet that restarts by itself

Here we go. I managed to enter Recovery mode. What are the next steps?

Thank you very much to Papiloulou61 for their advice.
So, after accessing the recovery, I went to wipe data factory reset, but unfortunately, my tablet still shuts down and restarts by itself, especially when I load an application. I'm afraid it might be worn out, right?
Thank you for your response.

Hello,
Do you have access to "Recovery" mode?

Can you please check if there is any storage space left? (in the settings)
Normally yes because of the factory reset!
Does it heat up quickly?

Hello, thank you for your response,
Actually, after a restart, I can still use my Samsung Tab S10.5 SM-T800. I changed the battery but the problem persists.
I'm not sure what to do,
Thank you for your response.

Hello Papiloulou61,
Oh dear. It seems quite complicated for me, who is not involved in this.
However, since I did a reset, I find that it "bugs" less. I'll try to keep it this way for now, hoping it doesn't get worse. Maybe one day I will come back to you (let's hope not).

I think there is enough space: 6GB used out of 16GB total. However, it is not very warm.

Hello,
Is this the model?
Samsung Galaxy Tab S 10.5 SM-T800 (WiFi)​
Possible overheating issue
No kidding, put the tablet in a plastic bag, put it in the fridge for a while
try to see if the startup goes a little further without functioning properly (if yes = motherboard defect)
Is the battery swollen (defective)?

Hello,
I tried "power and its +" but it didn't work, then with "power and its -" but there I accessed safe mode. I don't know how to get to "Recovery" mode.
Thank you for your response.
Best regards

Warning, everything personal will be lost (photos, videos, documents, music, SMS, MMS, contacts...)
as if the tablet were brand new...

Backup first!

If it is really unusable:
the last chance, complete reinstallation of the Android software (flash rom or firmware)
you would need to download the version (takes time if you are not a subscriber)
to find the reference, it's in the settings, software info, baseband version
T800XXU1ANH1 in this style

https://www.phonandroid.com/forum/threads/firmware-officiel-t800xxu1anh1-xef-android-4-4-2-kitkat-galaxy-tab-s-10-5-wifi-sm-t800.102838/

it seems complicated but it's doable