Very tactically, at the early stage valuations are mostly arbitrary.

Typically it goes by the market rate, geography, relative strengths of the investors vs founders, growth rates, ARR, etc.

For a $1M seed round (similar to filament):
A VC firm will look to get 10%-20%
A group of angels/seed will look to get 15-25%.
This is assuming you have some traction with good growth.

Your negotiating position and skill will determine which end of the scale it will be. The funding scene is also quite variable based on who you are, and hence YMMV.

[Advising 50+ startups in Microsoft Ventures, seen a dozen angel/seed/VC rounds up-close]