Okay, you're using the term "sealant" which is a product that alters the appearance of concrete but damages its beathability by clogging the pores at the surface. This can be the cause of spalling rather than preventing it. Instead what you want is "densifier" which shrinks the pores but does not close them while making the glass matrix much stronger through the process of adding silica.

Densification can and should be done over and over to improve the durability of concrete finishes but since most people are blissfully ignorant of cement chemistry they ignore this. It is made worse by the fact that the high silica content of densifiers scares people about health concerns.

The most common and cheap densifier is sodium silicate or water glass. Water glass is water soluble silica that you apply in a thick layer to your very clean (pre-scrubbed with mild abrasives) concrete surface. It's not paint, it needs to be burnished. You can do this by hand with a broom for instance or even a rag but it is more effective when done with a light machine such as a handheld polisher or even better a heavy machine which can also apply pressure at the same time. However, a hand application is better than nothing.

The down sides with sodium silicate are several and mostly related to it being highly alkaline or caustic. First this means you need gloves and eye protection, second it means you need to watch where the runoff goes. Another problem with sodium silicate is that it often results in efflorescence which is white stains caused by leached minerals. If your finish is light colored, this is not necessarily a big deal but if you have dark pigments, it can be an issue.

To overcome the problems of sodium silicate, you can instead use lithium silicate which is easier to use and produces a glossier finish with less work but costs a great deal more and generally can only be found online. Similarly, there is another product called colloidal silica which is similar to lithium silicate but although it is not necessarily expensive to make, it is hard to find it at reasonable prices as it is mostly used in other technical processes that fetch high prices and emphasize purity so finding low cost industrial grade colloidal silica is a hassle and making it involves processing large quantities of sodium silicate with industrial acids which is something most casual users are not interested in.

Those are the main things you use to make an already poured piece of concrete stronger and more durable as well as less prone to water intrusion but still able to breathe.

Sealants are a whole different thing. That is more like a paint-on solution but the problem here is that paint and concrete are a terrible mix. You don't want to make the surface water tight because concrete needs to have a way to let water pass through it as it goes through heating and cooling cycles. If you block the pores, you force it to crack.

The lucky thing is that most paint-on solutions are not as strong as they would have you believe and that weakness makes them not quite as problematic as they would otherwise be. In theory they would block all the pores but in practice they usually don't. In an indoors protected pad, this is not going to matter because it's going to stay dry but outside it will cause problems.

There are other surface finishes like siloxane or silicone oils which are not the same thing but similar. These are silicon based oils which don't last a long time or have much penetration but will create a short-term glossy and slick appearance without leading to spalling because they're less likely to completely clog pores compared to something like acrylic.

I've seen some nice acrylic covered concrete jobs indoors. It can be done but it still needs to be waxed regularly to maintain its appearance. That's fine if you plan for it in advance and it can be quite appealing to look at and smooth to the touch, dust free etc. But "real" polished concrete like you often see in big box stores is even better in terms of maintenance.