They're actively releasing them as audiobooks and graphic novels now!
That's awesome. I started my kid on the graphic novel recently. She's loving it https://www.amazon.com/Invasion-Animorphs-Graphix-K-Applegate/dp/1338538098/
Not just that, he straight up catfished Jake and had a LOT of fun hitting on him pretending to be someone else. Marco was queer all over the place.
Tangentially related, but the other day I was looking for a gif and realized that an Animorphs cartoon done in the style of X-Men Evolution would've been absolutely perfect, since Kurt in his image inducer form is literally just Marco.
On that note, shout out to Chris Grines's excellent graphic novel adaptation. There aren't many but he's hard at work on them and they're very, very good introductory material.
Are you reading the books or graphic novels? I started https://www.amazon.com/Invasion-Animorphs-Graphix-K-Applegate/dp/1338538098 with my kid - they loved all the illustrations!
They just started releasing a graphic novel version. https://www.amazon.com/dp/1338538098/ref=cm_sw_r_u_apa_fabc_8tObGb8V4C3EE