Fusion plants are expected to use molten salts to transfer heat which sounds like it can allow up to 55% conversion efficiency (vs as low as 30% for light water fission)

Molten salts come with engineering headaches but it also makes fusion a more convenient source of process heat for industry. A study on the ARC design, that is looking to have its physics validated in 2026 by the SPARC machine, found it could produce CO2 free ammonia for shipping fuel at little more cost than current methods by using its electricity and heat

also, when it comes to finding fusion steam engines boring, sometimes I fear the wrath of Isaac Newton when someone brings him from the past to show him our literally alchemy powered fission and fusion plants producing electricity in quantities more valuable than the worldwide gold trade

The private spherical tokamak company in the UK has become the second privately funded company to reach 100 million degrees in their test reactor, they recently worked out a five year co-op plan with the STEP group

The physics for the MIT company is being tested in the SPARC reactor under construction, they hope to run a burning plasma in 2026

If that works they'd like to build a 200+MW reactor by 2035. The UK's STEP design is not as strong as the MIT design so it would have a lower magnetic field, however per size and magnetic field it produces 8x more power. It has some notable disadvantages though which is why it's nice to see both being tried

There are several candidates for the first grid connected fusion reactor that plan to build before STEP. Ironically the doubt about it being the first grid fusion reactor is kind of backwards, it's not that it's so unlikely to work but that it's fairly likely others will work first

The big catch that remains may be whether they can be built to produce commercially competitive power