Thanks so much for reading in advance <3 !

Recently, the network from my router got insanly bad, even sometimes it went down and stopped suddenly; in the day when we use it and even in night when it must be really good.
I tried re-configuring so much things in the settings and reseting too, but nothing worked (I also tried to connect just and only my laptop too)
I also called and messaged the ISP provider several times, but also nothing really helped.

As a last option i wanted to check: Will it be better if I insterted the SIM card in my phone instead?
It was so surprising how difference it made, from (4 - 7Mbps) from the router to almost 70mbps from my phone, it is really insane!
and it made me think if my Router has a problem and should I buy a new one?
My router is a TP-Link router but from (Orange) provider, I really feel they limit the internet output on them, or maybe the router they give is really bad (My neighbor has the same router, same network subscription and has bad internet too)

I'm thinking of buying ( Archer MR600 AC1200 4G+ ) or ( Archer MR400 )
will it give me the same amount as my ( iPhone 12 pro max ) does? or is there something special about phones?
I really need to know to consider buying a new router from TP-Link and get rid of the one from my ISP provider 

Thanks a lot !