Sorry to hear of your loss - xx
i had a pair of sisters that were both 5yrs old, when I lost Dash to pneumonia, Libby was ok but she lost her sparkle - she didn't like being alone &craved company.
I don't have any local guinea rescues near me & the few general animal rescues had no guineas in at the time either, but i phoned the veterinary practice i go to & asked if they knew of any, the receptionist i spoke to said she'd had 4 guineas & now there was only 1 remaining, Ellie she was 5yrs old too- the kids had grown up,moved out & lost interest- so she wanted to give her some company.
Introductions went well for these two old ladies & Libby chirped upon meeting her new friend, she was so happy again, they snuggled together

unfortunately I lost Libby a couple of months later.
Ellie was 8yrs old when i lost her to multiple health issues, but she was an adorable piggy & taught the vets & myself so much, i think she was happy & enjoyed the 3 yrs i had her - her final companion was also a Grace

they were introduced when Grace was about 6months - she's 5yrs old roughly now - they always got on well too as i think they had a kind of mother/daughter type bond- although in no way related.
I must admit although i love the youngsters/babies, there's something special about the Golden Oldies, there's something satisfying about having them & letting them live out there days being loved & totally spoilt (not that i spoil my piggies at all... no, no, no

) but i know what you mean about the emotional side of oldies, they take a big chunk of you with them when they leave for rainbow bridge, which usually is sooner than the younger ones do.
If you could find a rescue locally they will often help you bond Hope to one of their piggies.
Good luck with your decision, chinny tickles for Hope & popcorn pain free over rainbow bridge little Grace RIP. xx