https://www.bitwig.com : it's basically Ableton live but next gen, where everything can be modulated
https://www.renoise.com : the modern tracker
https://www.beepstreet.com/ios/drambo : this one justifies buying an ipad, it's incredible
If don't want to pay full price for Bitwig, wait for their summer and winter specials which happen every year. They also have an educational discount.
Bitwig uses a subscription model for upgrades, but if you end your subscription, you retain access to the last version available during the subscription (plus minor updates to that version) for life. When you buy Bitwig, it includes a 1 year upgrade subscription. When you're on the subscription, you also get access to a rotating selection of content from Bitwig's partners (https://www.bitwig.com/circle/) in the form of license keys, but unfortunately, many of these partner tools don't work with Linux.
But I have to say the sounds and plugins it comes with are not on par with ableton, some presets really have me scratching my head and it took forever until they gave us a decent convolution reverb. For the longest time I was not able to get a simple sine-wave out of the synthesizers it comes with (wtf?). It's also worth mentioning that back in the days this DAW was promoted with a feature that lets you collaborate with others over the network, now 10 years later there is no more mention of this feature and I think most forgot it was even planned. Recently they tried to sell you stock-plugins for a premium but back-pedaled quickly. That is just ridicoulous after I sunk hundreds of dollars in their update plans.
That being said I still recommend it.
It's not uncommon for synths (even hardware ones) to come without a sine wave. In fact some of the most famous ones don't have it (hello TB-303, SH-101, Minimoog and many more...). Of course, now that we have the grid, we can have whatever waveform we like. Also FM4.