Hello.
You should read this paper: https://doi.org/10.25664/ART-0315
There are several keys that could help you.

Are you thinking of Lasiobolidium boudieri? I had already compared to that one but rejected the hypothesis for several reasons. My spores seem to have a large guttule, so I thought there has been one or more guttules also in the livig state while mature spores of boudieri should have no guttules. Also the spore width is smaller than in your description. The hair bases are not either very clear. And the norternmost known boudieri is so far from Denmark. It is a very long way from Denmark to central Finland.

Or do you have something else in mind?

Here one more similar fungus, collected in southern Finland 27 years ago. On elk dung. This should definitely be a Lasiobolidium. Let us call this one specimen B and the one above specimen A, if commenting.

Dry apos are up to 2 mm wide. The marginal hairs are up to 1000 µm, with a bulbous or tapering base, no furcation observed. The margin has "pseudopoils" to 125 × 31 µm. The spores are 15.0-17.2 × 8.1-9.4 µm, eguttulate, Q on avg. 1,84. 8-spored asci.

L. macrocystis should have hairs with a furcate base and slightly larger spores. The spores are somewhat small, but I suppose this one must belong to the L. coprophilum complex. Right?

Undoubtfully this second collection belongs to L. coprophilum complex.
For the first one, it is a bit more difficult because we cannot see the content of spores in living state, but probably also a Lasiobolidium species

Oddly enough, in the same box with specimens of Pezizles from the nineties I found tonight still a third one related to the other two, specimen C.

This one was growing inside a hollow trunk of Populus laurifolia very recently logged, in a park in western Finland. The two apos are now 3,5 and 5 mm in diameter. My notes say the hymenium was somewhat yellowish when collected. They are growing on a thick white hyphal mat. I don't know does the mat belong to this species or perhaps to Rigidoporus populinus growing close by; at least there are no clamps.

The marginal hairs are up to 1400 µm, almost all hairs with a bulbous base and in addition a few hairs of the Trichophaeopsis type with the base "in the middle". There were also some ±clavate thick-walled "pseudohairs" with light brownish walls, up to 190 × 56 µm. The spores are smooth, eguttulate, 17.7-22.1 × 10.0-12.7 µm, Qm = 1.75. Asci 8-spored.

I presume this one does not have a name.

This third species seems to be Lasiobolidium boudieri

Thank you again! The reason I excluded L. boudieri was "L. boudieri [...] can be distinguished by the absence of large marginal macrocells". But other than that it is a fairly good match, even though the spores are somewhat large.