There is a fundamental difference between both.
Spiritual people are the seekers and practice and believe in things based on the experiences. But religion is based on faith, and faith is blind.
Religion knows everything, so, a religious person. But a spiritual person doesn’t know everything because life keeps evolving. A spiritual person won’t say that she/he knows everything because spirituality has no boundary.
Religions are organised, everything is written and pre-defined that what happens after death and who goes where. That’s not a case with spirituality. A spiritual person keeps learning throughout life and keeps evolving with time, and the only reason is that there is no set boundary in spirituality. Spirituality gives freedom to all types of beliefs and opinions. But, in religion, the boundaries are defined, and you can’t question its existence.
I could take an example of Open Source platform where source code could be modified, e.g. UNIX/Linux. There is non-stop upgrade and evolution in an open source platform. If you are a great programmer, you can go ahead and make changes based on your capabilities, and there is no limit on it. If you are a great seeker and on the spiritual path, there is no end to attain spiritual heights. Entire universe belongs to you.
Religion is not an Open Source platform. The source code is locked, and you are not allowed to modify anything in that. You have to use and believe in what is given to you; there are always limitations. The upgrades are not possible in an organised religion, and if you try to do so, you will face enough trouble. That’s why after a certain point, it stops answering all the questions.