Space Tourism site built with Astro

I haven't figured out the best way to make transitions to make the user experience more pleasant, what do you guys figure? If I were to use a framework it would be overkill and unecessarily slow down the website. View Transitions API is not stable yet, so probably will not that any time soon. If I coded my own solution in vanilla JavaScript I think it would be overwhelming to take into account accessibility stuff (navigable history between pages, and respond to it when keyboard shortcuts are used, like <alt><left> to go backward or <alt><right> to go forward) and overall make a well-rounded solution. Please help...