Mineral oil is called paraffin oil in Australia. Food grade paraffin oil (ie the laxative stool softener) can be used on chopping boards but does not cure or dry.

Good luck I’ve had mixing equal parts of tung oil, beeswax, and turpentine. Very nice satin finish, good feel and fragrance. I always add a dryer to tung oil in any application. Dries much quicker, i.e., several hours. Wet sand in tung oil cut~ 10-20 % with turpentine. I use a lot of drier, maybe 10-20 % of the mix. Drier can be purchased in an art supply store. It is often added to oil paint.

Shellac can be topped with varnish.

First off, I get that this is an old thread. I would still like to throw in my two cents simply for the people who still read thru these posts with the intent of gaining useful knowledge from people who have “been there, done that” (professionals) and to get ideas from people who have been or are currently in similar situations. With no disrespect to any of the above replies, I would like to offer a solution.
The OP stated that she needed something durable as the table is in heavy use and gets all sorts of traffic… daily. She also stated that the two previous attempts with poly failed due to the wear and tear of such traffic. The mention of peeling might suggest the finish failed from underneath due to poor adhesion. Either way, the last thing you want to do to any piece of furniture that needs protection from daily use (especially a dinner table) is wax it. Wax offers ZERO protection. None at all. At least not the kind of protection that she is looking for. From the limited information the OP gave, I have to think there is only one logical option. Conversion varnish. It will give the protection that she needs from just about everything a typical dining table will encounter… water marks, scratches etc.
Yes, it will have to be taken to a refinisher but in the end she will get what she wants. Protection from daily use.
Yes, there are other options. Most of them that are as durable or more so will be reflected in the cost.
I have been working in our family restoration business for just shy of 40 years. with a large percentage of that time devoted to applying finishes to wood. Aside from polyester and some of the 2K automotive acrylic urethanes, conversion varnish is as durable a finish as u could find and in my opinion, the best option..
The wood looks to me like rift or even plain sawn red oak. However, pecan, white oak and even some cuts of hickory are very very close.

In early coats I thin my pure oils. For my first coat I thin my tung oil to 25% with 75% thinner. My second coat I use 50% tung 50% thinner. The third coat 75% tung with 25% thinner. Each coat after I use 100% tung. I do this because thinned oil with permeate the surface of the wood ever so slightly better (I understand this is a disputable opinion) and it also allows the oil to dry more quickly. This is helpful since pure tung oil dry times can be upwards of a week (depending on temperature and humidity) and you should wait for the oil to dry between coats.

If unfinished you can use whatever finish you want. Considering it is a high wear surface.

Doesn’t look like oak to me. If the bannister is still unfinished, you should be able to stain it.

Please forgive me I know nothing about varnish, its maintenance requirements, its limitations, etc.

Thanks!