while verizon is there ask them to install a central DSL filter, and
either you or them run a dedicated line from filter to computer modem.
ask for filter when calling so tech has it on truck, mine was free

no more phone filters, new line has low losses, and much more
reliable.

this should end forver your issues.

old lines are a main cause of flakey DSL. i had these issues here,
central filter and new dedicated line to computer ended that hassle
for good