my kitten never shuts up

i adopted a male kitten about 2 months ago. hes now 8 months. he literally meows constantly. hes only quiet when hes sleeping, eating, or playing.

i got him from a cat lounge where there was 30+ cats so im sure he was never bored. unfortunately my older cat passed about 2 weeks after i adopted my new kitten, so hes alone all day while im at work. i would not have adopted him if i knew hed be alone all day, i thought him and my late cat would keep each other company.

anyways he has plenty of toys, im routinely giving him new ones to keep him entertained. i have a feliway plug in to help with stress. im not sure if hes bored but im in no way capable of getting another cat friend for him right now.

is there a way to train him to stop meowing so much? its getting to a point where i feel like im going crazy. ive had cats my whole life and have never experienced this. hes been like that since the day i adopted him. any advice?