Sqlite can take more than you think
Your question is part of a false premise. First this is a value thought about 10, 15 years ago and was well, very conservative, and does not consider appropriate techniques to increase this capacity. The Sqlite has improved a lot since then, the hardware has improved (SSD, NVRAM coming), thought of better techniques, and in practice could always more.
I think it’s naive to post that value, because capacity can’t even be measured that way, it has a lot of false premises in that information, and worse not have updated.
Note that the official page is talking about a web server that has concurrent access and not a mobile device that does not usually have concurrent access. Actually the page says that only 1% of websites are not suitable. So it is another false premise.
My experience is that in fact 0.1% are not suitable for Sqlite (considering all, even those that not even a DB needs), if used correctly. Do you think you will be one of the 1% most successful sites in the world? That means you will be one of the 20 or 30 largest Brazilian sites. Even if one day it happens, you will have so much money coming from this site that you can hire the best professionals and buy the best tools to solve your problem.
Even the most sophisticated databases often need auxiliary tools, suitable techniques to withstand. This site you’re using now is one of the 30 most accessed in the world. It uses SQL Server, but the ability to handle all of this is not because SQL Server is excellent, it’s because the engineers who take care of the site are excellent. There’s a much smaller site that used SQL Server, Oracle, Mysql, and other things and opened its mouth. Why? Whoever did it didn’t know what they were doing. Without understanding how things work any tool can be the wrong one.
See more about where it can be used for real.
Swap out the DB
You can always change the database, but I doubt that one day you will need to use Sqlite on the web server (I just can’t guarantee it in all scenarios). If you are going to use mobile you will never have to change, because the hardware of a mobile phone can’t handle doing so much operation, Sqlite is less of your problems. But I imagine you’re only saying this because you think you have thousands of connections on a mobile device. And it’s another false premise.
If you think people will install Mysql, Oracle, etc. on your phones, you are very much mistaken. Not that I can’t, but this is crazy that I’ve never seen anyone do it except for an experiment.
Other databases
As already said Sqlite can meet millions of requests a day if used correctly. This is more than nearly every website in the world needs. But if on the server want another DB, and even there are reasons for it, but not because Sqlite is not good, the most used for web is Mysql, although many people are preferring Mariadb which is a Fork mysql.
You can also use other relational databases or not, but the decision of the correct tool goes through a deep analysis of very experienced people to get it right. If you are struggling with something so basic, it is best to go for the simplest (Sqlite) and hire specialized people when you need something sophisticated.
That’s what I always say, people need to learn how things work, check on their own, and not believe what’s written out there, most of the information available on the internet is wrong. Because there is little canonical information, and even this may be wrong, as is the case, and there are copies of distorted canonical information, such as a wireless phone.
"it is not recommended to use it on sites with more than 100 thousand requests per day" I found it kind of arbitrary. If it is essentially reading, I see no problem.
– Bacco