It's been said many times, but fuel excise tax is not quarantined for road infrastructure, so no, it's not "one of the main ones" - fuel excise goes into consolidated revenue, the government of the day decides through budget allocation how much of total revenue is spent on infrastructure in balance with all other funding requirements. EVs may not contribute directly to fuel excise but they are more expensive on average, they are predominantly charged through purchased mains electricity etc etc so contribute to tax revenue elsewhere anyway. By eliminating tailpipe emissions they also contribute to reduced health system costs associated with pollution and don't contribute to urban heat island effects etc in the same way as ICE vehicles so there are other downstream cost reductions that benefit the whole system.
In this context, it is a direct disincentive to the uptake of EVs, which is already hampered by the lack of the sorts of incentives other jurisdictions have established - as you've noted re: congestion charges etc. At this point, when EV uptake is so low, we need to reduce the barriers to uptake, not increase them.
If fuel excise is not bringing in the revenue it once did, then it should be supplemented by congestion/emissions charges on all vehicles (i.e. majority ICE). A PAYG levy should be reserved until such a time as EVs represent a significant enough proportion of road stock (and are well enough supported, cheap enough etc as a result) to both not be a barrier to transition, and also be able to raise enough revenue to actually be worthwhile.
As is is, these taxes seem likely to cost more than they raise anyway, because there will continue to be fuck all EVs (meaning revenue raised will be low), and we'll still be having to cover the various costs associated with more and more Hiluxes and Rangers on the road from the diminished/diminishing funding envelope.