If you are idling the boiler at 190F you are paying HUGE standby losses, and probably paying to remove that excess heat in summer via air conditioning. That's more than a 100F difference in temperature between the boiler room air and the water temp, and this boiler isn't exactly super-insulated! Most boilers with embedded coils can be idled at 150F in summer, 160F in winter and still deliver sorta-reasonable hot water performance, as long as the coil wasn't completely limed up. At 150F the standby losses will be reduced by more than 25% from a boiler standing by at 190F.
If the gauge was indicating 120F or something the water would be pretty tepid, but should be fine with a 190F boiler.
It's remotely conceivable that it's not the boiler at all, and that the tempering valve at the output of the coil is sticking. The tempering valve mixes cold water with the coil output to reduce the water going into the hot water distribution plumbing to safe levels. If it is malfunctioning and feeding more cold water than it should the output would be tepid no matter what the boiler temp was, until the vibration from flow gets it past it's sticky point.
Have a competent tech come debug the system, but have them quote installing an indirect HW heater, and have them include a heat-purging economizer control (eg. Intellicon 3250 ) as part of the package. With an indirect and an economizer control the standby temp can safely be reduced to ~140F without negatively impacting hot water performance, and at typical 3x over sizing would reduce wintertime oil use by 10-15%, and cutting summertime oil use by 25-30%. You need enough space for the indirect tank (it doesn't need to be right next to the boiler, if somehow it doesn't fit):
The smarter controls would probably add something like another $300 to the quote if quoted as a package, $500-600 if done after the fact, though as a DIY for those with electrician skills it can cost ~$200, sometimes less.
With typically oversized oil boilers smarter controls pay for themselves in less than one heating season at the recent 5 year average price of heating oil, and still less than 2 heating seasons at this past winter's lower oil pricing.