Hello,
As I post infrequently I cannot contact you but if you care to contact me I can tell you about the TP Link MR6500v. I have been using it for a while after my Huawei routers which operated on VOIP ceased to work because of the frequency changes to cellphones i.e. the demise of 3G.
This router uses VOLTE which now seems to work quite well, but initially was a PITA. It appears all providers are now using VOLTE - voice over long term evaluation, and it has progressivly improved. I have it conected to my DECT phone, but it is difficult to explain to contacts that although it has a mobile number it is in fact a "home" phone. With my provider - Talkmobile - I get free calls and texts and 150Gb /month for £9.95. The previous routers from Huawei - B818-263 - are Cat 19 and excellent for 4G reception but no longer work on VOIP as it has been superceeded