router Administration is weak if do it strong crashed

[techdepths]

I updated my Asus AC87U firmware to ASUSWRT-MERLIN 380.62 then
try to set 50 characters long password for Administration password of Asus AC87U router, it set it ok but when I went back to login, I canot enter long password in password textbox, I realised the password box lenght limited to 18 I increased it to 50 manuallt by browser developer tools and put the user name and password to login to Asus AC87U with Asus,
it logined but all UI crashed and missy, any fix to enable us put a strong password for router Administration.

 

[RMerlin]

I updated my Asus AC87U firmware to ASUSWRT-MERLIN 380.62 then
try to set 50 characters long password for Administration password of Asus AC87U router, it set it ok but when I went back to login, I canot enter long password in password textbox, I realised the password box lenght limited to 18 I increased it to 50 manuallt by browser developer tools and put the user name and password to login to Asus AC87U with Asus,
it logined but all UI crashed and missy, any fix to enable us put a strong password for router Administration.

If I increase that limit, and you switch to an older firmware or to the stock firmware, you will be locked out of the router. That's the reason why I cannot safely increase that limit.