Very slow draining of washing machine. Same Master plumber I used in 3/2018 for same reason came out this July. Told last year that wye was installed backwards when piping replaced in 2002. No clogs between ‘02 and ‘18. After 4 hrs of snaking clog couldn’t be removed. I was told I need to tunnel about 12’ to correctly install wye and clear clog. On my own I used 2 treatments of Safe Drain Opener by Xion (enzymes) and it helped just a little. Now backs up after most of an extra small load (older type machine) drains. Scared to use lye based or other drain cleaners that are caustic even if product says safe for all types of pipe. Area that would be tunneled backfilled with slurry so may need jack hammer ( extra $750 ish per day on top of other cost). Can a wet dry vac help? Water-jetting? Hard to think backward wye is the issue when it worked great for 16 years and then clogged twice in 15 months. For 12 of those months 1 more person moved in who did a lot of laundry. Before it was just me with less and smaller loads. Note: Snake inserted in Kitchen sink goes up wall behind washer. ALL HELP APPRECIATED. I am homeowner with no plumbing expertise.