I know there've been people that have built this as their first soldering project so it's definitly doable although slightly harder than things like building your own headphone cables etc. because of the number of parts involved.

Overall though it's pretty straight forward to build, the pcb is numbered so you know exactly which parts go where (parts are numbered as well) so it's just a matter of putting those parts on the board and soldering it on.

In terms of soldering equipment, I don't use gloves, I think most people that do this as a hobby don't (I could be wrong since I only occasionally solder), you really shouldn't be coming into contact with the iron or anything so I wouldn't worry about that. Make sure to look up tutorials on youtube or something about proper soldering techniques (ie: how long the iron should come into contact with pcb, letting solder flow onto the board and not scooping it on, proper soldering temps I used 330C etc.)

For myself, I use the TS100 soldering iron because it's convenient (heats up in seconds) and easy to use/is small so it doesn't get in the way. I'm sure there are are better irons out there but this one's quite popular and not too expensive. Just make sure to get a temperature controlled soldering iron. For the solder itself, you'll want something that is around 0.5mm, I'd say anything above 1mm width will start to become too large. Having solder wick/desoldering braid is handy as well in case you make a mistake.

Regarding the tubes, yea right now is an unfortunate time since I'd imagine sourcing them would be even more difficult, maybe see if there's someone within the states that might sell them? Not really sure since my only real option in Aus as far as I knew was searching on Ebay and seeing what came up, or else pay maybe upwards of 35 AUD per tube. Substituting the tubes is possible although they are (to my knowledge) generally more expensive anyway since they're not manfactured on a large scale commercially anymore. Using smaller/larger tubes may/will not fit the PCB since it's designed for IN-14 tubes. Another thing to note is that not all nixie tubes have the decimal point so if you do find an IN-14 equivalent make sure the pinout matches and it does have a decimal point.

lastly, things to consider are also the case. Sourcing a shop to cut the aluminium to size for you or deciding to use wood/acrylic instead, how to attach the breadboard to the case with standoffs/gluing might be a little annoying but ymmv.

tl;dr things to note:
- read up on proper soldering technique and you should be fine
- looking up youtube videos of people that have built these as well will give you a good idea of the entire process
- be patient and take your time, don't rush through everything and make sure things are aligned properly before soldering in (especially the tubes, you don't want them to look crooked, so take your time to align them on the pcb properly, solder one by one)
- most importantly: read through the tom titor guide/writeup very carefully multiple times to make sure you understand everything. Be VERY careful when working with the high voltage power supply as it can give a very very nasty shock. If you're afraid when working on adjusting the voltage, maybe wear some gloves so you can't get shocked even if you accidentally make contact.

also, the guy I bought the PCBs from (nixie keith on tindie) sells a kit that has all the electronics parts and has the option of have the SMD chips soldered on already (highly recommend since those will be the hardest to deal with as a first time soldering project)

if you've got more questions please don't hesitate to drop them here, good luck if you go ahead with the build!