Selection of the optimal sealer choice for my project

Submitted to Product Chat

Hello. I am refurbishing-restoring my consignment shop handcrafted wooden bird houses (used for decorative display only) with latex acrylic ...sadly for a second time.

The bird houses are displayed on a deck screened porch that exposed to seasonal temperature fluctuations but somewhat sheltered from actual rain and snow unless severe winds persist.

After I get all my decorative painting completed what would be your suggestion for the best sealer choice either aerosol spray or paint on sealer to help protect the bird houses recent acrylic latex paint restoration. Hope to prevent the aging and deteriorating the brittle chippy finish that I just eliminated.
I would hope for a matte for satin finish not high gloss.

Additionally could you please educate me:

Do all sealers yellow with aging?
*Constructed many years ago (>10) a multiple coat sealer application to a cornhole set has yellowed most prominently on the white background.
I am not sure if its an expected outcome or something related to my sealer choice or application or the way my son has stored it.
*Maybe 20 years ago painted a bird and birdhouse on a metal mailbox and with time and weather exposure the sealed decorative painting also yellowed.

Considering putting acrylic Spar Varathane on top of a decorative wooden tabletop accent stenciling.
Not sure if white is used - if it might be affected with time.

Thank you very much for your help with your expert recommendation! Educated choices help for best results and product performance expectations.

Kindest regards