Why not Python? I've never seen huge differences between Jinja, Razor, or Blade. Is there something about it you find extra annoying?
With FastUI, you write Python.
Not every web app needs to survive HN levels of traffic. Empowering the <insert profession here> that already knows Python to make an app to automate their team’s toil is a great thing.
I say this with absolute conviction; you're just deferring costs, technical debts with compounding interest. When you come to pay it off, it'll bankrupt you.
Jinja:
{% for item in items %}<br> {{ item }}<br> {% endfor %}
Blade:
@foreach(var item in items)<br> {<br>@item<br> }