I believe the "context" indicates that there is only one unforgiveable sin of blasphemy against the HS (Matt.12:31),
and so Jesus must have been referring to the unforgivable sin of apostasy Paul described in Heb.6:4-6,
or else there would be two.
You may have no trouble with Scripture contradicting itself, but I prefer harmonizing when possible.
There is no contradiction because you failed to see the ones blaspheming the Spirit in Matt. are unbelievers. The believers in Hebrews are not blaspheming the Holy Spirit they are shaming Christ. You are not harmonizing scripture you are stretching what only an unbeliever can do to make a believer do it. It is simply not possible for a believer to blaspheme the Holy Spirit. Can they blaspheme God? Yes, because Jesus said there is more than one type of blasphemy.
Matthew 12:31
“Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men.
Matthew 12:32
Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come.
You are trying to compare apples and oranges. Those who blaspheme the Holy Spirit do not believe, have never believed and never will believe which is why they will not be forgiven.