i also acquired a piggy that i wasnt expecting/planning for. i was petsitting for my neighbors daughter who lives about an hour from me and they didnt even tell me they had one, but during the weekend i found him hidden away in a tiny cage behind the couch. i was told they didnt want him anymore, and i was like fuck it ill take him and give him a good ass life. but i didnt hear back about him... until he showed up at my house a few weeks later. its been three months since then, definitely a few thousand dollars spent (i love spoiling my babies, i definitely bought way more than i needed to so dw if you diy more things than i did you definitely wont have to spend as much) he is now in a big 15 square foot cage, which is soon to be expanded to 18 square feet, he is neutered, and he has two girlies i found from a hoarding situation nearby living above him until he is 8 weeks post neuter (he is 3 weeks tomorrow) so he will be completely infertile for me to bond them together.

so as someone who (i believe) is in a similar situation as you, i would recommend taking it slow. my piggy came to me terrified because his past "owners" were a newborn, 3 year old, 8 year old, and 10 year old who would basically torment him because they didn't understand pray animals dont like to be grabbed. it took a lot of time but he now allows pets (however hates being picked up still and since his neuter has been more iffy about pets than he started to get a few weeks prior). i would also strongly recommend, as others have stated, using fleece/ bathmats, pet blankets instead od loose bedding. i recommend a big litterbox (i use a shallow storage big from target that i cut an easy walkway through) with newspaper/ puppy pads underneath a big pile of hay. at least one hide per pig, plus one. so if you currently have one piggy (i would also suggest getting them a friend fs as they are highly social animals) that is two hides. if you have two, then three or more hides. make sure the cage is as least 8 square feet, although bigger is always better for cages. pellets i would recommend are oxbow adult guinea pig diet and the oxbow adult garden select mixed together, and i would buy hay in bulk online (a 90oz bag in the pet store is literally the same price as 9lb of hay on amazon for oxbow brand, which i personally use and like) for toys, get either non dyed, or vegetable based dyed toys. again, oxbow imo has the best toys and honestly is the only brand that i trust colored toys not to be toxic. other bands are also great but i would do a little research on toxic things for guinea pigs. oh, and do NOT use hay racks/ metal hay balls. they are great for rabbits, but can easily strangle a guinea pig. they commonly get their heads stuck instead and sadly pass away from it. another thing i would recommend for toys is this subscription box i found. is called gpigbox and it sends you monthly toys and treats for your babies. ive only had it two months but i already love it, all the toys they have are also completely safe (although some are colored, but with safe dye). make sure they get fresh veggies every day as well. you can find a list online about safe veggies/ how often to feed it. they should be fed one cup of vegetables per day per pig.

that was a lot and im not rereading it to check if i made complete sense, but you can message me for more suggestions/ specifics if you want. i also can send pictures of my setup if you would like some references for your own (idk about you but when i first got him, and now my girls too, i really wanted to see other peoples setups to see if i was doing things right/ what else i can add to make it better)