Adequate speed for a Wi-Fi repeater
You can find important differences between one model and another. There are those that are dual band and others that only work in 2.4 GHz, there is also a difference in the protocol they use (Wi-Fi 5, Wi-Fi 6, etc.) and in terms of coverage. All this can make them have more or less speed.
When buying a Wi-Fi repeater you will have information about the theoretical top speed that they have, if they are dual band and the protocol with which it is compatible. Some typical speeds that you will see are 300 Mbps, 600 and 1200. Some models, the more advanced ones, can offer even more.
You must take into account the fiber optic rate that you have contracted. If, for example, you buy a repeater that has a maximum speed of 300 Mbps and you have 1 Gbps fiber optics, not even in the best of cases could you take advantage of that speed. You would always be limited and could not download or upload files taking advantage of the maximum capacity of your network.
The ideal is to have a repeater that has at least the speed your router accepts and can support the maximum speed of the rate you have contracted. For example, if you have 1 Gbps fiber optics, which is becoming more common, and you have a router that supports 1200 Mbps, you should have a repeater that supports 1200 Mbps.
You can see some options:
Choose a quality repeater
But you should not only look at the theoretical maximum speed, which is important, but in other aspects. It is essential that you buy a quality wireless repeater, that you can take advantage of properly. Ultimately, the idea is to be able to cover a large area of your home and have coverage to connect other devices.
Something that you should also take into account for speed is whether or not it has ethernet port. If you are going to connect equipment by cable, it is interesting that it has a Gigabit Ethernet port and thus be able to connect a computer, game console, television or any compatible device and have greater stability than through Wi-Fi. But it is important that it is Gigabit and not Fast Ethernet, since then you can reach up to 1 Gbps and not be limited to 100 Mbps.
Another important point is the number of devices supported. Ideally, it can support quite a few, since you surely want to connect many devices. If you buy a low-quality one, as soon as you connect 4 or 5, you will see that the quality decreases a lot. Others, on the other hand, admit even more than 30.
In short, as you can see, the speed of the Wi-Fi repeater is important. Always try to buy one that admits at least what you have contracted. Although it does not mean that you will receive that, since it will depend on the distance and other factors, at least you will have that as a possibility. It is important to differentiate between access point and Wi-Fi repeater.